This invention relates to a dust filter unit of the kind that comprises a plurality of flexible filter bags that are open to the clean air side and mounted on cages that prevent the bags from collapsing. The invention relates also to a method of cleaning such a filter unit.
It is common in the art to utilize a heavy reverse flow to clean the filters. The reverse flow carries dust with it out from the filter unit. Another method is to induce a propagation of a wave in the filter bags by means of low velocity air pulses that are introduced into hose filters through wide openings so that the air pulses will be as wide as the hoses. None of these methods are very efficient. Mechanical vibrators have also been used but they reduce the life of the filter bags substantially.
It is an object of the invention to provide for a fast and efficient cleaning of such filters with a minimum of wear and without introducing a heavy reverse flow.